This project will continue ongoing applied research concerning outpatient treatment for narcotics addiction and poly-drug abuse. Operating in collaboration with a community methadone maintenance program, this project will conduct behavioral pharmacological studies concerning four specific components of treatment program operation: 1) Dispensing studies: Experiments will evaluate the extent to which methadone's effects upon patients (i.e., symptomatology, subjective dosage evaluation) are determined by pharmacological variables (i.e., dosage) versus behavioral/environmental variables relating to suggestibility (e.g., instructions, expectations, knowledge of dose, volume of medication); 2) Detoxification studies: Experiments will evaluate the relevance of various behavioral and pharmacological parameters to the successful detoxification of addicts from methadone as measured by client retention, symptomatology, and illicit drug supplementation; 3) Abstinence studies: Experiments will evaluate the effectiveness of behavioral contracting and contingency management procedures in achieving drug abstinence in programs focusing upon either routine urinalysis monitoring or maintenance of narcotic antagonist (naltrexone) ingestion; 4) Maintenance studies: Experiments will evaluate whether resources available within the operation of a methadone maintenance program (e.g., take-home privileges, medication dosage self-control, financial incentives) serve as reinforcers to patients and whether their incorporation into contingency management treatment plans can effectively reduce illicit supplementation of narcotics and sedatives and be used to support adaptive positively-directed behaviors.